The effect of induced stress on long-term memory in lymnaea stagnalis

Abstract

Lymnaea stagnalis is a pond snail that has proven useful for studies of learning and memory of aerial respiration. Aerial respiration is an easily quantified behaviour that is controlled by a central pattern generator whose necessity and sufficiency has been directly demonstrated. If snails are exposed to an aversive chemical stimulus ( causes a defensive behaviour without causing permanent harm) before or after conditioning, a training schedule that normally only results in intermediate-term memory, causes long­term memory persisting at least 24 hours. A single application of an aversive chemical stressor is also capable of forming long-term memory if the application is contingent with pneumostome opening. Therefore training related to stress or a particularly aversive stimulus is enhanced and, therefore, results in long-term memory. This memory has many of the same characteristics as memory from more extensive training but is, in general, more resistant to manipulation after consolidation.